Many containers, particularly plastic bottles containing dispensing fluids (whether, e.g., drinkable liquids or cleaning fluids), have closures or caps which are twisted or pulled to open a passage for dispensing the liquid, and provide a seal to close the container and prevent leaking when not in use.
In one such conventional cap structure, a tip is slidable over a central stem on the shell of the cap, with the shell defining an opening around the stem for dispensing the fluid. A plastic tip is slidably secured over the stem and includes a central opening which seals around the stem to block fluid when the tip is pushed in, with the central opening being spaced from the stem to allow fluid to be dispensed around the stem and through the tip opening when the tip is pulled out. Closures of this type are shown, for example, in U.S. Pat. Nos. 5,472,120 and 5,975,369, the complete disclosures of which are hereby incorporated by reference.
The connection of the tip to the shell of the closure is particularly important for commercial acceptance of such closures. For example, it is important that the force required to push the tip to close the container, and to pull the tip to open the container when releasing, be within acceptable ranges. Consumers will not accept caps which are too difficult to push closed or pull open. At the same time, caps which open too easily are also undesirable in that they may be unintentionally opened and leak liquid from the container. Still further, it is important that the cap be capable of being easily assembled while at the same time have its components sufficiently secured together so that the possibility of them coming apart (and essentially destroying the usefulness of the cap) is minimized. Secure retention of the movable tips of such caps can be particularly difficult to provide given that the tip of such caps can be subjected to many different forces, including not only axially directed loads such as used to the tip open, but also side and twisting loads. Side loads can be particularly large when, for example, a user bites on the tip during use (e.g., when drinking from the container) as is not uncommon.
The present invention is directed toward overcoming one or more of the problems set forth above.